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EFFECTS OF EFFECTIVE MICROORGANISMS ON PROPERTIES
OF BLENDED CEMENT CONCRETE
NURUL AS’SHIKIN BINTI RAMLI
A project report submitted in partial fulfilment of the
requirements for the award of the degree of
Master of Engineering (Civil)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
JUNE 2017
iii
“Dedicated to my beloved husband Meor Shahrizan bin Zolkfle,
my son Daniyal Anaqi bin Meor Sharizan, and family for their love,
encouragement and support.”
“Special thanks to supervisor, all lecturers, and friends for their motivation, concern
and help.”
iv
ACKNOWLEDGEMENT
First and foremost, all praise and thanks to Allah the exalted for His blessing
in giving me opportunities to complete this project report.
Special appreciation goes to my supervisor, Assoc. Prof. Dr Abdul Rahman
bin Mohd Sam for his supervision and constant support. The invaluable help from
him in constructive comments and suggestions throughout the experimental and
project works have contributed to the success of this study.
I give my appreciation and thankful especially to my beloved husband Meor
Shahrizan bin Zolkfle, my parents, and my precious son Daniyal Anaqi on the
encouragement and support throughout this study. My appreciation also goes to all
the structural and material laboratory staff, who had taught on how to operate the
machine, setting up test and others.
Finally, thanks to all my friends who have happen to help me in carrying out
this project. Every single helps means a lot for this study success. Hopefully this
study will be blessed by Allah and will benefit for future.
v
ABSTRACT
Concrete is an artificial rock that is made with a mixture of cement, aggregates
and water with certain proportion. Concrete is one of the material that is most widely
used in the construction industry. Cracks that occurs in concrete structure require
regular maintenance and special type of treatment which will be very expensive,
particularly to the massive concrete structures that bear loads or main structures
members. So, to overcome this problem, EM (Effective Microorganism) concrete is
introduced to study the potential of EM concrete in filling the cracks. By mixing EM
with concrete mixture, the effect on the properties of concrete is assessed whether
this EM concrete increase the workability, strength, durability and other properties
related. In this study, understanding the function and mechanism of EM in concrete
is crucial. Several parameters and concrete properties was tested in the experimental
procedure and the effect of EM in concrete were assessed in this study. The
performance of EM were measured through its fresh and hardened properties of the
concrete. From this experimental study, the optimum EM mix to be added in the
concrete is 10%, slump of EM concrete had increase by 11.4%. Compressive
strength of the EM concrete also increase and modified compression strength is
higher than cube compressive strength by the average of 5%. UPV value were
increasing by 4%. The EM concrete had higher shrinkage and expansion strain.
Water absorption shows that concrete with dry curing condition does absorb more
water. EM concrete shows lower rate of carbonation process than control concrete by
50%. From this study, it can be concluded that the properties and behavior of EM
concrete almost similar with the normal concrete. EM concrete does have the
potential in filling the crack of concrete and further studied is crucial in
understanding the mechanism and reaction of EM in concrete.
vi
ABSTRAK
Konkrit merupakan batuan tiruan yang diperbuat daripada campuran simen,
aggregat dan air dengan nisbah yang tertentu. Konkit merupakan salah satu bahan
yang digunakan secara meluas di dalam industry pembinaan. Keretakan yang terjadi
di dalam struktur konkrit memerlukan penyelenggaraan dan pemuliharaan yang
berkala dan mahal, terutamanya kepada struktur konkrit besar yang menanggung
beban atau struktur utama. Jadi, bagi mengatasi masalah ini, mikroorganisma efektif
(EM) diperkenalkan untuk mengaji potensi EM ini dalam menutupi keretakan
konkrit. Dengan mencampurkan EM dalam campuran konkrit, kesan ke atas sifat-
sifat konkrit dinilai sama ada konkrit EM ini meningkatkan kebolehkerjaan,
kekuatan, ketahanan dan sifat-sifat lain yang berkaitan. Dalam kajian ini, memahami
fungsi dan mekanisme EM di dalam konkrit adalah amat penting. Beberapa
parameter dan sifat-sifat konkrit telah diuji dalam prosedur eksperimen dan kesan
EM di dalam konkrit telah dinilai dalam kajian ini. Campuran optimum bagi
spesimen EM yang menyumbang kepada sifat-sifat kekuatan maksimum adalah 10%
EM dalam bahan tambah konkrit, ujian penurunan meningkat sebanyak 11.4%,
kekuatan kiub konkrit EM lebih tinggi, dan kekuatan mampatan diubahsuai adalah
lebih tinggi daripada kekuatan mampatan kiub dengan purata 5%. Bacaan UPV
meningkat sebanyak 4%, menunjukkan bahawa EM berpotensi untuk menutupi
keretakan konkrit. Konkrit EM mengalami pengecutan dan pengembangan spesimen
yang lebih tinggi. Kebolehtepalan air menunjukkan konkrit dalam pengawetan udara
menyerap lebih banyak air berbanding konkrit yang diawet di dalam air. Konkrit EM
menunjukkan kadar pengkarbonatan yang lebih rendah sebanyak 50%. Daripada
kajian ini, dapat disimpulkan bahawa sifat-sifat dan tingkah laku konkrit EM hampir
sama dengan konkrit biasa dan berpotensi digunakan dalam bancuhan konkrit.
vii
TABLE OF CONTENT
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENT vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF ABBREVIATIONS/SYMBOLS xiii
1 INTRODUCTION 1
1.1 Background of Study 1
1.2 Problem Statement 3
1.3 Objectives of the Study 4
1.4 Scope of Study 4
1.5 Significant of Study 5
2 LITERATURE REVIEW 6
2.1 Introduction 6
2.2 Causes of Cracks in Concrete Structure 8
2.2.1 Plastic Shrinkage 10
2.2.2 Plastic Settlement Cracks 11
2.2.3 Plastic Shrinkage Cracks 12
viii
2.2.4 Early Thermal Cracks 13
2.2.5 Long Term Drying Shrinkage Cracks 13
2.3 Limiting Crack Width for Self-healing 14
2.4 Self-healing Phenomena (State of Art) 15
2.5 Self-healing Mechanism 22
2.5.1 Mechanisms of Autogenic Self-healing 24
2.5.2 Mechanisms of Autonomic Self-healing 25
2.5.3 Mechanisms of Natural Healing 27
2.6 Effective Microorganism 27
2.7 Bacterial Concrete 30
2.7.1 Mechanisms of Bacterial Concrete 31
2.8 Advantages of Bacterial Concrete 32
2.9 Disadvantages of Bacterial Concrete 34
3 METHODOLOGY 37
3.1 Introduction 37
3.2 Experimental Study Plan 37
3.3 Material Used 40
3.3.1 Blended Cement 40
3.3.2 Aggregates 41
3.3.3 Water 42
3.3.4 Effective Microorganism 42
3.4 Concrete Mix Design 44
3.5 Optimum Mix Design Proportion of EM 44
3.6 Preparation of Specimen 45
3.6.1 Casting 46
3.6.2 Curing 46
3.7 Pre-Loading of Specimen 47
3.8 Experimental Test 48
3.8.1 Slump Test 48
3.8.2 Compressive Strength Test 49
3.8.2.1 Procedure for Compression Test 50
3.8.3 The Ultrasonic Pulse Velocity (UPV) Test 51
ix
3.8.3.1 Principles of Operation 52
3.8.3.2 Procedure of the UPV Test 53
3.8.4 Water Absorption Test 54
3.8.4.1 Procedure of Water Absorption Test 56
3.8.5 Flexural Test 57
3.8.5.1 Flexural Test Procedure 58
3.8.6 Modified Compression Test 59
3.8.6.2 Modified Compression Test Procedure 60
3.8.7 Expansion and Shrinkage Test 60
3.8.7.1 Expansion and Shrinkage Test Procedure 61
3.8.8 Carbonation Test 62
3.8.8.1 Carbonation Test Procedure 62
4 RESULT AND DISCUSSION 64
4.1 Introduction 64
4.2 Optimum Mix Design Proportion of EM 64
4.3 Slump Test 66
4.4 Development of Concrete Compressive Strength 67
4.5 Ultrasonic Pulse Velocity (UPV) 70
4.6 Surface Water Absorption 76
4.7 Flexural Strength Test 77
4.8 Modified Compression Test 79
4.9 Expansion and Shrinkage Test 80
4.10 Carbonation Test 81
5 CONCLUSION AND RECOMMENDATION 83
5.1 Introduction 83
5.2 Conclusions 83
5.3 Recommendations for Future Project 85
REFERENCES 87
x
LIST OF TABLES
TABLE NO TITLE PAGE
2.1 Permissible crack width for self-healing. (Source: Self-
Healing Phenomena in Cement Based Materials,
Reinhardt (2013))
15
2.2 Examples of Elements Belonging to each set in Figure 2.6
according to JCI TC-075B
19
2.3 Approach of Autonomous Self-Healing 26
3.1 Composition of Concrete Mixture 44
3.2 Types of Specimen 45
4.1 The Amount of Percent EM in concrete Mix 65
4.2 Slump of Specimen 66
4.3 Compressive Strength of Specimen 69
4.4 UPV Value for Concrete Specimen without Pre-Crack
(km/s)
73
4.5 UPV value for Concrete Specimen with Pre-Crack (km/s) 75
4.6 Flexural Strength Test Value 78
4.7 Modified Compression Test vs Cube Compression Test
Results
79
xi
LIST OF FIGURES
FIGURE NO TITLE PAGE
2.1 Examples of intrinsic cracks in hypothetical structure
(Source: Concrete Society, 1992)
10
2.2 Plastic Shrinkage Cracking (Source : ACI 301-05) 11
2.3 Formation of plastic settlement cracks (initial and final
state). (Source: Advanced Concrete Technology;
Concrete Properties, 2003)
11
2.4 Process of plastic shrinkage cracking (initiation and final
state) (Source: Advanced Concrete Technology; Concrete
Properties, 2003)
12
2.5 Drying shrinkage cracks on wall. Vertical lines indicate
the position of reinforcement. (Source: Advanced
Concrete Technology; Concrete Properties, 2003)
14
2.6 Venn diagram to explain terminology of self-healing
according to JCI TC-075B. (Source: Self-Healing
Phenomena in Cement Based Materials, Rooij (2011))
19
2.7 Concept of performance recovery by a healing function.
(Source: Self-Healing Phenomena in Cement Based
Materials, Rooij (2011))
20
3.1 Methodology Flow Chart 38
3.2 Blended Cement 40
xii
3.3 Course Aggregates 41
3.4 Fine Aggregates 41
3.5 Effective Microorganism (EM) 43
3.6 Curing Condition of the Specimen 47
3.7 Slump Test 49
3.8 Uniaxial Compression Load Test 50
3.9 Ultrasonic Pulse Velocity (UPV) Test 51
3.10 Schematic Diagram Water Absorption Test (source from
ASTM 1585-04 International)
55
3.11 Flexural test 58
3.12 Modified Compression Test 59
3.13 Digital Demec Gauge 61
4.1 Optimum Percentage of EM in Concrete Mix 65
4.2 Slump Test 67
4.3 Compressive Strength for Control and EM Concrete 68
4.4 Failure Mode Pattern 70
4.5 UPV Test for all Specimen 72
4.6 Water Absorption, I (mm) vs √Time (s) Graph 77
4.7 Failure Mode Pattern of Prism Specimen 79
4.8 Shrinkage and Expansion vs Age Graph 80
4.9 Carbonation Test on Fresh Fracture Concrete for both
Specimen
82
4.10 Carbonation on Control and EM Specimen in Air Curing
Condition
82
xiii
LIST OF ABBREVIATIONS/SYMBOLS
ACI - American Concrete Institute
ASTM - American Society for Testing And Material
BS - British Standard
CCRA - Cube Control Air Curing
CCRW - Cube Control Water Curing
CPRA - Cube Pre-Crack Air Curing
CPRW - Cube Pre-Crack Water Curing
ECRA - EM Cube Control Air Curing
ECRW - EM Cube Control Water Curing
EM - Effective Microorganism
EPRA - EM Cube Pre-Crack Air Curing
EPRW - EM Cube Pre-Crack Water Curing
JCI - Japan Concrete Institute
PCRA Prism Control Air Curing
PCRW Prism Control Water Curing
PEA Prism EM Air Curing
PEW Prism EM Water Curing
RILEM The International Union of Laboratories and Experts in
Construction Materials, Systems and Structures
UPV Ultrasonic Pulse Velocity
CHAPTER 1
INTRODUCTION
1.1 Background of Study
Concrete is one of the important material that is commonly used in the
construction industry. Concrete is the main material used for the infrastructure
development in every country. Concrete is made from the mixture of cement, water,
aggregate and sand with certain proportion to produce a slurry. Cement is a binder
that bind other materials together.
In concrete, cracking is a common phenomenon due to the relatively low
tensile strength. High tensile stresses can result from external loads, imposed
deformations (due to temperature gradients, confined shrinkage and differential
settlement), plastic shrinkage, plastic settlement, and expansive reactions (e.g. due to
reinforcement corrosion, alkali, silica reaction, sulphate attack. Without immediate
and proper treatment, cracks tend to expand further and eventually require costly
repair. Durability of concrete is also impaired by these cracks, since they provide an
easy path for the transport of liquid and gasses that potentially contain harmful
substances. If micro cracks grow and reach the reinforcement, not only the concrete
itself may be attacked, but also the reinforcement will be corroded when it is exposed
2
to water and oxygen, and possibly carbon dioxide and chlorides. Micro cracks are
therefore precursors to structural failure (Tittelboom et al., 2013).
Self-healing is actually an old and well known phenomenon for concrete as it
possesses some natural autogeneous healing properties. Autogeneously crack-
healing capacity of concrete has been recognized in several recent studies. Mainly
micro cracks with widths in the range of 0.05 to 0.1 mm have been observed to
become completely sealed particularly under wet and dry condition. The mechanism
of this autogeneously healing is chiefly due to secondary hydration of non or
partially reacted cement particles present in the concrete matrix. One possible
technique is currently being investigated and developed was based on application of
mineral producing bacteria in concrete.
Although bacteria and particularly acid producing bacteria, have been
traditionally considered as harmful organisms for concrete, recent research has
shown that species such as ureolytic and other bacteria can actually be useful as a
tool repair cracks or clean the surface of concrete. Bacteria can act as catalyst for the
metabolic conversion of a suitable organic or inorganic component. The nature of
metabolically produced filler materials could be minerals such as calcite (calcium
carbonate). These minerals are relatively dense and can block cracks, thus increase
some of the concrete properties. The development of a self-healing mechanism of
concrete that is based on potentially cheaper and more sustainable material thus be
beneficial for both economy and environment.
3
1.1 Problem Statement
Concrete structures often suffers from cracking that lead to much earlier
deterioration and designed service life. To prevent such deterioration, regular
inspection of cracks in concrete structures and their repair are usually carried out by
means of some kind of human intervention. Cracks in concrete can occur in any
stage of the service life of concrete structures due to volume instabilities such as
autogenous shrinkage or drying shrinkage since concrete is composed of aggregate
of various sizes connected with the hydration process generated by mixing water and
cement. Once cracking occurs in reinforced concrete members, not only the stiffness
reduced but steel bars corrosion also occurs due to permeation of rain, harsh weather
and aggressive substances, reducing structural safety and serviceability. The
availability of self-healing concrete would make structures more reliable. For
example, if control and repair at the early stage cracks in concrete structures were
possible, permeation of factors for deterioration could be prevented, thus extending
the service life of the structures. In the meantime, sustainability is now one of the top
issues in the field of building and civil engineering from the viewpoint of global
ecology. Besides that, precipitation on calcium carbonate due to biochemical action
of bacteria has been expected to be one of the new technologies for self-healing
concrete that can be applied in the future.
From Jonkers et al. (2008), a high crack healing potential of concrete
structures is beneficial as it makes the material stronger and above all more durable.
A continuous healing of particularly surface cracks results in decreased permeability
of the material and a significantly reduced risk of premature matrix degradation and
corrosion of the embedded steel reinforcement due to ingress water and aggressive
chemicals.
4
1.2 Objectives
The main purpose of this study is to determine the effects of EM on the
properties of concrete including fresh and hardened state. Following are the
objectives of the study.
i. To determine the optimum percentage of Effective Microorganism (EM)
in blended cement concrete mix.
ii. To determine the effects of Effective Microorganism (EM) on fresh and
hardened properties of concrete.
iii. To investigate the effects of Effective Microorganism (EM) on self-
healing process of matured concrete.
1.3 Scope of Study
The scope of this study is to focus on applying Effective Microorganism in
concrete as the healing agent. Cracks are formed due to plastic shrinkage, drying
shrinkage and thermal effects when the concrete are not properly cured. The porosity
of concrete produce more voids and the crack allows water and oxygen into the
concrete. The idea is that after cracking, mixed in EM on fresh concrete crack
surfaces are activated in the presence of water, and then start to multiply and
precipitate minerals, such as calcite, and close or seal the crack.
5
1.4 Significant of Research
Approach of using EM in concrete as self-healing agent makes very
beneficial compared to the conventional concrete. Based on these study, if EM
concrete does give some effects towards self-healing approach and potential through
its reaction mechanism in concrete, then EM concrete could be one of the important
material in the future construction. When EM concrete is apply in construction
industry, it may become another alternative method to repair concrete cracks
internally. The approaches of self-healing concrete can provide ways in reducing
maintenance work due to cracking and increase durability of concrete structure, high
strength buildings with more bearing capacity, retaining liquid structure which are
more detail design especially focused for preventing cracks for a long term period.
87
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